Changeset: 0c91ad69feba for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=0c91ad69feba
Modified Files:
monetdb5/mal/mal_authorize.c
sql/backends/monet5/sql_gencode.c
Branch: remote_auth
Log Message:
Handle aborted transactions correctly wrt remote table creation
When `AUTHaddRemoteTableCredentials` finds an existing entry for the
table it was called for, we can safely overwrite this entry. See the
comment at the function for more details.
diffs (66 lines):
diff --git a/monetdb5/mal/mal_authorize.c b/monetdb5/mal/mal_authorize.c
--- a/monetdb5/mal/mal_authorize.c
+++ b/monetdb5/mal/mal_authorize.c
@@ -1046,8 +1046,49 @@ AUTHaddRemoteTableCredentials(const char
p = lookupRemoteTableKey(local_table);
if (p != BUN_NONE) {
- /* key already in, just return */
- return MAL_SUCCEED;
+ /* An entry with the given key is already in the vault (note: the
+ * key is the string "schema.table_name", which is unique in the
+ * SQL catalog, in the sense that no two tables can have the same
+ * name in the same schema). This can only mean that the entry is
+ * invalid (i.e. it does not correspond to a valid SQL table). To
+ * see this consider the following:
+ *
+ * 1. The function `AUTHaddRemoteTableCredentials` is only called
+ * from `rel_create_table` (also from the upgrade code, but this
+ * is irrelevant for our discussion since, in this case no remote
+ * table will have any credentials), i.e. when we are creating a
+ * (remote) table.
+ *
+ * 2. If a remote table with name "schema.table_name" has been
+ * defined previously (i.e there is already a SQL catalog entry
+ * for it) and we try to define it again,
+ * `AUTHaddRemoteTableCredentials` will *not* be called because we
+ * are trying to define an already existing table, and the SQL
+ * layer will not allow us to continue.
+ *
+ * 3. The only way to add an entry in the vault is calling this
+ * function.
+ *
+ * Accepting (1)-(3) above means that just before
+ * `AUTHaddRemoteTableCredentials` gets called with an argument
+ * "schema.table_name", that table does not exist in the SQL
+ * catalog.
+ *
+ * This means that if we call `AUTHaddRemoteTableCredentials` with
+ * argument "schema.table_name" and find an entry with that key
+ * already in the vault, we can safely overwrite it, because the
+ * table it refers to does not exist in the SQL catalog. We can
+ * also conclude that the previous entry was added in the vault as
+ * part of a CREATE REMOTE TABLE call (conclusion follows from (1)
+ * and (3)), that did not create a corresponding entry in the SQL
+ * catalog (conclusion follows from (2)). The only (valid) way for
+ * this to happen is if the CREATE REMOTE TABLE call was inside a
+ * transaction that did not succeed.
+ *
+ * Implementation note: we first delete the entry and then add a
+ * new entry with the same key.
+ */
+ AUTHdeleteRemoteTableCredentials(local_table);
}
if (pass == NULL) {
diff --git a/sql/backends/monet5/sql_gencode.c
b/sql/backends/monet5/sql_gencode.c
--- a/sql/backends/monet5/sql_gencode.c
+++ b/sql/backends/monet5/sql_gencode.c
@@ -277,7 +277,6 @@ static int
MalBlkPtr curBlk = 0;
InstrPtr curInstr = 0, p, o;
Symbol backup = NULL;
- // const char *uri = mapiuri_uri(prp->value, m->sa);
const char *local_tbl = prp->value;
node *n;
int i, q, v;
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